Yup. But you'll note it is inserted at the point of the glass, NOT in the bowl where the product is. The latter is what one really wants to measure. I've run those tests before.
If it is inside the bowl, the measurement is right on point. When you draw, and therefore introduce foreign air (heated or not) into the bowl, the temp remains on point. Stop draw, on point. Turn on fan assist, on point.
I just have a digital multimeter, but I've seen output on live graphs before. The curve, once Herbie is turned on and up to temp, is surprisingly flat, despite activity. That's something you just don't see and one of the big selling points here regarding this device's accuracy.
In addition to being able to maintain a fixed temp across conditions, I'll add the that that each unit is individually calibrated by hand before it is put in it's box.